Some LNBs are manufactured which have a waveguide at right angles to a support housing which carries a printed circuit board with circuitry for receiving electrical signals and probes which extend through the rear wall of the waveguide. Such LNBs are particularly sold in the United States and South American market.
With some probe designs, the probes are located in dielectric bushes and the probes are also not straight but are arranged so that the tips of the probe are bent, such that when the probes are located within the waveguide, the leading portion of the tip is in proximity to the septum or the waveguide wall so as to provide capacitive coupling between the probe and the waveguide. The probes effectively form a coaxial transmission line between the waveguide rear wall and the PCB by virtue of the fact that they are positioned on the centre line of a symmetrical aperture in the housing. The ends of the probe are located in the dielectric bushes and the bush/probe assembly is, in use, connected to the printed circuit board which sits on a housing at right angles to the main axis of the waveguide. Such an arrangement is disclosed in applicant's co-pending U.K. Application No. 9928095.0.
The probes are soldered to the circuit board. This means that the probe/bush assembly has to be carefully positioned and soldered to the circuit board. The circuit board is then fastened to the housing and then covered. Should there be a fault in the circuit board which requires board removal or the probe is incorrectly oriented in the waveguide, then this requires that the probe(s) be de-soldered from the board so as to allow the probes and the board to be extracted from the LNB.
In situ, this is very difficult. Even in the laboratory, the probes have to be de-soldered, the board removed and then the probes extracted from the waveguide. Assembly requires the reverse of the process which is time-consuming and inconvenient.